# decoherence
## English
### Etymology

First attested 1902 (OED) in the electrical engineering sense "the resetting of a coherer." From decohere (also 1902) +‎ -ence, representing the verbal noun (compare decohesion, decoherency). The quantum mechanics concept was introduced in 1970 by German physicist H. Dieter Zeh, writing in the journal Foundations of Physics.

### Pronunciation

* (UK) IPA: /diːkəʊˈhɪəɹəns/

### Noun

decoherence (countable and uncountable, plural decoherences)
* (quantum mechanics) Loss of quantum coherence (phase relation between the quantum states of particles) in a physical system as it interacts with its environment.
** 1999, Jeffrey A. Barrett, The Quantum Mechanics of Minds and Worlds, Oxford University Press, page 221:There is a sense in which simple interference effects are destroyed when a system's environment becomes correlated with its state. This phenomenon is called decoherence. I shall consider three approaches here. According to one, decoherence alone explains why we get determinate records. According to another, decoherence helps one to formulate a satisfactory interpretation of Everett by selecting a globally preferred basis that makes the right physical facts determinate in each Everett branch. According to a third, decoherence sects a locally preferred basis for each observer that makes the right physical facts determinate from the perspective of that particular observer.
** 2004, Friedel Weinert, The Scientist as Philosopher: Philosophical Consequences of Great Scientific Discoveries, Springer, page 272:We have already alluded to decoherence in connection with the emergence of classical space-time, the ‘collapse′ of the wave function (Case 3) and the notion of entanglement. Physicists have hailed the discovery of decoherence as ‘the most important advance in the foundation of quantum theory since Bell's inequalities.’$^{131}$ This praise is based on good reasons: (a) decoherence offers new ways of understanding quantum mechanics for it embodies a critique of entrenched terminology (‘collapse’ of the wave function, complementarity); (b) it is testable since it appeals to physical processes; (c) it offers an insight into a much more fundamental level of quantum indeterminacy.
** 2008, D. Klauser, W. A. Coish, Daniel Loss, “Quantum-Dot Spin Qubit and Hyperfine Interaction”, in Rolf Haug, editor, Advances in Solid State Physics, 46, Springer, page 20:A detailed investigation of decoherence during gating due to a bosonic environment was performed in the original work of Loss and DiVincenzo. Since then, there have been many studies of leakage and decoherence in the context of the quantum-dot quantum computing proposal.
** 2015, Fernanda Samaniega, “Manipulating Spins: Causality and Decoherence”, in Uskali Mäki, Ioannis Votsis, Stéphanie Ruphy, Gerhard Schurz, editors, Recent Developments in the Philosophy of Science: EPSA13 Helsinki, Springer,, page 191:One way of preventing both decoherences is to set up the system in a "non-decoherent quantum state."
* (engineering, dated) The normal condition of sensitiveness in a coherer; reversion to such condition.

#### Synonyms

* (quantum mechanics): decoherency, quantum decoherence

#### Derived terms

* decoherence time
* predecoherence

#### Related terms

* coherence
* decoherent

#### Translations
### See also

* dephasing
* einselection
* quantum entanglement
* quantum interference

### Further reading

* Coherence (physics) on Wikipedia.Wikipedia
* Dephasing on Wikipedia.Wikipedia
* Einselection on Wikipedia.Wikipedia
* Wave function collapse on Wikipedia.Wikipedia
* Measurement problem on Wikipedia.Wikipedia
* Quantum entanglement on Wikipedia.Wikipedia
* Wave interference on Wikipedia.Wikipedia